1. Structure of skin. 2. Skin relating problems : a. Dry skin b. Acne c. Pigmentation d. Prickly heat e. Wrinkles f. Body odour 3. Structure of hair. 4. Hair growth cycle.

1. Cosmetics –
Biological Aspects.
Presented by
Sarang V. Dalvi
M. Pharm (Pharmaceutics)
VBCOP Amravati.
2019 - 2020

2. CONTENTS
1. Structure of skin.
2. Skin relating problems :
a. Dry skin
b. Acne
c. Pigmentation
d. Prickly heat
e. Wrinkles
f. Body odour
3. Structure of hair.
4. Hair growth cycle.
5. References.

3. Structure of skin and
Relating problems.

4. INTRODUCTION
• Skin is the largest body organ which weighs about 4kg
and an area of 2m2.
• It performs many vital functions, including protection
against external physical, chemical, as well as
prevention of excess water loss from the body and a role
in thermoregulation.
• Three layers of skin :
• Epidermis
• Dermis
• Hypodermis

5. LAYERS OF SKIN
EPIDERMIS
• Outer layer that is s barrier to infection “superficial”
• Made up of stratified squamous epithelial cells.
• Avascular.
DERMIS
• Middle layer that contains nerves, Hair roots.
• Sweat and oil glands and blood vessels.
HYPODERMIS
• It contains Fats, blood vessels and connective tissue that help to maintain
body temperature.
Fig : Layers of skin.

6. Fig : Microscopic cross-section of skin.

7. EPIDERMIS
• Epidermis is primarily made up of stratified squamous
epithelium.
• Epidermis doesn't contains any blood vessels.
• Epidermis thickness ranges from less than 0.1mm (on
eyelids) to 1 mm (on palm and sole), the thickness is kept
constant by cells dividing in the deepest layer (basal or
germinative layer).

8.  Layers of Epidermis
Epidermis divided in to different regions or strata:
• Stratum corneum
• Stratum lucidum
• Stratum granulosum
• Stratum spinosum
• Stratum basale (Stratum germinitivum)

9. Fig : Microscopic layers of epidermis.

10.  Stratum Corneum
• Its Most superficial layer of skin consisting of dead cells
corneocytes.
• The stratum corneum is the rate limiting barrier that
restricts the inward & outward movement of chemical
substances.
• This layer is responsible for the "spring back" or stretchy
properties of skin.
• The stratum corneum exhibit regional difference in
thickness over the body.

11. • It is thick on the palm of the hand & soles of the feet in an
adult.
• Stratum corneum contain a dense network of keratin, a
protein that helps keep the skin hydrated by preventing
water evaporation.
• These cells can also absorb water, further aiding in
hydration.

12.  Stratum lucidum
• Stratum lucidum is seen in thick skin of the palms and
soles of feet.
• It contains 3-5 rows of clear flat dead cells.
• Its mainly composed of ‘keratohyalin’ which is precursor to
keratin.
 Stratum granulosum
• It contains 3-5 rows of flattened cells.
• Its mainly composed of ‘keratohyalin granules’ (darkly
stained)

13.  Stratum spinosum
• Also known as “spiny layer”
• It contains 8-10 rows of polyhedral (many sided) cells
• It has the appearance of prickly spines.
• It mainly contains melanin granules and Langerhans’ cell.
 Stratum basale
• Also known as “stratum germinativum”
• It’s the deepest epidermal layer.
• Its attached to dermis
• Its composed of single row of cells, mostly columnar
keratinocytes.

14. DERMIS
• Dermis lies between the epidermis and subcutaneous
layer and contains many type of sensory receptor for
touch, pressure, vibration, pain, temperature etc.
•The type of cells located in the dermis are:
• Fibroblasts, Mast cells, Histocytes.
• Hair follicles, nerves.
• Lymphatic vessels and blood vessels.
• Sweat glands and oil glands.
• Dermis contains two layers:
• Papillary layer
• Reticular layer

15. Fig : Microscopic layers of dermis.

16.  Papillary layer
• Its composed of loose connective tissue with small surface
projections called “Dermal papilla”.
• It contains:
- Capillaries
- Pain receptors
- Touch receptors (Meissner’s corpuscles)
- Dermal ridges (pattern called fingerprints)
 Reticular layer
• Its dense irregular in nature.
• It contains collagen fibers and offer strength.
• It holds water to provide hydration.

17. HYPODERMIS
• Its known as subcutaneous tissue or Sub-Q.
• It consist of loose connective tissue with collagen and
elastic fibers.
• Main type of cells in hypodermis are :
• Fibroblast
• Adipose tissue
• Macrophages
• Functions as:
• Energy source
• Provides Insulation
• Its common site for injection
• It anchors skin to underlying structures

18. SKIN RELATING PROBLEMS
 Dry skin
• Dry skin has a low level of sebum and can be prone to
sensitivity. Dry skin refers to roughened or scaly skin that
is less flexible than normal and dry to feel.
• The dry skin is the common problem in all age groups, but
more in elderly individuals.
• The water content of the stratum corneum play important
role for maintaining the normal appearance and texture of
skin.
• It looks dull, mainly on the cheeks and around the eyes.

19. Causes :
• Poor diet, nutritional deficiencies and especially
deficiencies of vitamin A and the vitamin B can also
contribute to dry skin.
• Harsh soaps, itchy clothing, exposure to sun, cold
environment, chemicals and long hot showers.
• If the oil glands do not produce enough lubrication to the
skin it may lead to dry skin.
• Medications you take and even medical conditions such
as diabetes, hypothyroidism, malnutrition can also cause
severe dry skin.

20. Care for dry skin :
• Skip long hot shower, Hot water strips oils from the skin
faster than warm water.
• Use a gentle cleanser or shower gel with moisturizer.
• Go for soap free or mild soap cleansers instead of harsh
cleanser.
• Moisturize while skin is moist moisturizer increases the
water content of the outer layers of skin and gives it a soft
look.

21.  Acne
• Acne is an inflammatory skin condition that occurs when
oil and dead skin cells blocks the pore opening causing
sebum to build up in side the pores.
Causes :
• Genetics is the primary cause of acne in 80% of cases.
• Hormonal activity, such as occurs during menstrual cycles
and puberty may contribute to the formation of acne.
• Stress can causes or worsens acne.
• Several medications can worsen pre-existing acne.
Examples of such medications include hydantoin,
isoniazid, testosterone.

22. Treatment :
• Useing cleansers for oily skin toners help to
remove excess sebum.
• Avoid using fatty skin care and cosmetic
products; use non comedogenic
products(designed and proven not to clog the
follicles).
• Do not use harsh products or over clean acne-
prone skin as this can lead to inflammation.
• Use anti-androgen, anti-biotic like tetracycline,
cotrimoxazole to stop growth of bacteria and reduce

23.  Pigmentation
• Pigmentation refers to the colouring of the skin. Skin
pigmentation disorders cause changes to the colour of
your skin.
• Skin gets its color from pigment called melanin.
• It occur due to the deposition of the melanin, which is
produce by specialized cells called melanocytes.
• Type of pigmentation :
• Hyperpigmentation
• Hypopigmentation

24. • Hyperpigmentation means that the skin looks darker
than normal (often brown to grey). This is the more
common response after inflammation.
• Hypopigmentation means that the skin looks lighter than
normal.
Fig : Hyperpigmentation Fig : Hypopigmentation

25. Causes :
• Eczema
• Psoriasis
• Skin allergies (contact dermatitis)
• Injury To the skin
• Insect bites
• Acne
Treatment :
• Topical prescription medication such as 4% hydroquinone
are often use to treat Hyperpigmentation.
• Aloe Vera contain aloin, a natural depigmenting
compound.

26. • Over the counter brightening product that contain licorice
root, pine tree, vitamin E, vitamin C.
• Drugs used to treat pigmentation :
• Corticosteroids, azelaic acid
• Trichloro acetic acid retinoic acid
• Glycolic acid

27.  Prickly heat
• The condition that we call prickly heat, also known as heat
rash, happens to adults and children when sweat
becomes trapped under the skin.
Fig : Prickly heat

28. Causes :
• Heat rash is caused by a blockage of the sweat gland,
especially after repeated sweating, leading to
inflammation which causes itching, prickling sensation and
red rashs, which may be extensive.
Treatment :
• Remain in a cool environment e.g. air conditioning, or
close to a fan, and allow for adequate ventilation of the
skin.
• Take cool showers or baths several times a day and
always after exercise or heat exposure.
• Use cool packs on affected areas

29.  Wrinkles
Wrinkles are lines and furrow that form in your skin. These
are especially noticeable around your mouth, neck, hands,
and eyes.
Fig : Wrinkles

30. Causes :
• Ageing
• Repeated facial expression
• Exposure to uv-sun light
• Smoking
Treatment :
• Topical retinoids: Derived from vitamin A, retinoids can be
applied to skin to reduce fine wrinkles, splotches and skin
roughness.
• Antiwrinkle creams.
• Rhytidectomy: is a type of cosmetic surgery procedure
used to give a more youthful facial appearance.

31.  Body odour
Body odour is the perceived unpleasant smell our bodies
can give. Body odour caused by the combination of sweat
and bacteria normally found in skin.
Causes :
• Body odour is caused by bacteria breaking down sweat
and is largely linked to the apocrine glands.
• Excessive sweating.
Treatment :
• Keep the armpits clean
• Use deodorant or antiperspirant:
• Have a shower or bath at least once a day
• Clothing: Natural fibers allow your skin to breathe,
resulting in better evaporation of sweat.

32. Structure of hair and
Hair growth cycle.

33. • Hair is a simple structure that is made up of Protein
filaments called Keratin.
• The main functions of Hair are :
• Thermo regulation
• Protection
• Facilitation for evaporation of perspiration
• Heat insulation on head
• Trichology - Branch of medical science that study hair
and its diseases and care.
• Hair is made up of two separate structures
1. The hair root : which exists below the skin.
2. The hair shaft : which is the hair that we see.

34. Structure of Hair root
• Hair follicle : tube-like depression or pocket in the skin or
scalp that contains the hair root.
• Hair bulb : lowest part of a strand of hair; thickened, club-
shaped.
• Dermal papilla : small, cone-shaped elevation located at the
base of the hair follicle that fits into the hair bulb.
• Arrector pili muscle : small, involuntary muscle in the base of
the hair follicle; when it contracts, we get goose bumps.
• Sebaceous glands : oil glands in the skin that are connected
to the hair follicles; secretes sebum (fatty, oily substance)

35. Fig : Hair root structure.

36. Structure of Hair shaft
• The shaft has three layers:
• Cuticle (outer layer)
• Cortex (middle layer)
• Medulla (inner layer)
The medulla is a honeycomb keratin structure with air
spaces inside.
The cortex gives flexibility and tensile (stretching) strength
to hair and contains melanin granules, which give hair its
colour. its cortex is made from tiny fibers of keratin running
parallel to each other along the length of the hair shaft.

37. • The cuticle is made from 6 to 11 layers of overlapping
semi-transparent keratin scales (which make the hair
waterproof and allow it to be stretched).
Fig : Layers of hair shaft.

38. HAIR GROWTH CYCLE
• The three stages of hair growth are the
1. Anagen Phase
2. Catagen Phase
3. Telogen Phase
• Each strand of hair on the human body is at its own stage
of development.
• Once the cycle is complete, it restarts and a new strand of
hair begins to form.
• The rate or speed of hair growth is about 1.25 centimetres
per month, or about 15 centimetres per year.

39. Fig : Hair growth cycle.

40. Anagen
• Anagen is the hair growing
phase. Hair growth rate is
about 3 mm per week.
• It begins in the papilla and can
last from two to six years.
• The longer the hair stays in
the anagen phase, the longer
it will grow.
• About 85% - 90% of the hairs
on one's head are in the
anagen phase at any given
time
Fig : Anagen.

41. Catagen
• The catagen phase is a short
transition stage that occurs at
the end of the anagen phase.
• This process cuts the hair off
from its blood supply and from
the cells that produce new
hair.
• This phase lasts for about 2–3
weeks and then the hair
follicle enters the telogen
phase.
Fig : Catagen.

42. Telogen
• The telogen phase is the
resting phase of the hair
follicle.
• Fifty to one-hundred club hair
are shed daily from a normal
scalp.
• Then, when telogen ends,
hair germ cells start growing
a new hair follicle from the
dermal papilla and the next
hair growth cycle starts
again.
Fig : Telogen.